I figured out why everyone else could beat SF4 while I couldn't. I was playing on easy, thinking it was the easiest difficulty. It turns out the not only is there a "Very Easy" but there is a Very Very Easy, called "Easiest". The first time I played through it was as M.Bison and all I did was down kick over and over again and I won never died. I even got a perfect on Seth. So, now I can unlock all the characters. That doesn't address my balancing complaints about Seth in multiplayer, but I've learned some new tricks, so I might do better next time someone plays as him.